Continuous motion packaging machines, including those machines which package articles such as beverage containers or food containers, typically group a selected number of articles into a desired configuration, and package those articles in a carton or carrier formed from a paperboard blank. For example, when packaging beverage containers, such as bottles or cans, the articles are grouped into a predetermined configuration or pattern, and either moved singularly or as a group into an open, preassembled carton. In another configuration, a "wrap-around" paperboard blank is folded or wrapped around the preconfigured article group. In either case, the packaging of the article group into the paperboard blank occurs while the article group is being conveyed along a path of travel from an infeed area to an outfeed area. This allows the articles to be packaged in a continuous operation, which normally carries on without interruption.
Many types of paperboard carriers, in particular the wrap-around type, are manufactured of paperboard blanks including fold lines, score lines, and preformed flaps, such as article stabilizers or reinforcing flaps. These reinforcing flaps serve to restrict article movement and prevent contact of adjacent articles once the carrier has been wrapped around the article group and tightened or locked, usually by the insertion of locking tabs in one bottom panel and in apertures in another bottom panel. A typical reinforcing flap, for example, would merely be a portion of the side panel of the formed carrier defined by partial cuts or score lines therein.
Accordingly, when dealing with paperboard blanks, the reinforcing flap is a part of, and is aligned with the side wall of the blank. As the paperboard carrier is wrapped around a bottle group, however, the reinforcing flap is not automatically biased into its final position in which it projects inwardly from the side wall and into the bottle group, but must be moved into the appropriate orientation.
Specific flap folding mechanisms have been developed to bend or fold reinforcing flaps into the proper orientation, which step usually occurs just prior to the tightening of the carrier around the bottle group. In many of these operations, the mechanism must engage a specific area of the carton in a particular manner to accomplish the desired folding step. Considering that the operation must be accomplished while the carton is in continuous motion along a path of travel, often at high speeds, and that only a specific area must be engaged, the folding mechanism must be designed to operate in timed relationship with the moving carton. Additionally, such wrap-around cartons include several flaps, perhaps as many as two or three flaps per side, which must be folded to reinforce and separate adjacent articles.
In the past, flap folding mechanisms have included numerous engaging devices which were sequentially aligned with the prescored flap areas of the carton side panel, pushed into the carton side panel to fold the flap to a first extent, and then operated to fold the flaps even further. The engagement devices then would be sequentially removed from the prescored areas in the carton side wall and the carton locked around the article group. A problem associated with a sequential flap folding process, however, is that when the first engagement device is fully activated to fold the flaps to the furthest extent, often the entire carton is shifted in the direction of the path of travel.
Since the transverse alignment of the moving carton with the engagement mechanism is critical, carton shifting can have a significant effect on the entire processing operation. If a carton is shifted to a great extent, the subsequent engaging mechanism does not appropriately align with the prescored flap area, and the remaining, sequentially disposed engagement mechanisms will impact the carton side wall at a position other than a prescored flap area and often bend or tear the carton. In high speed packaging operations, this can interrupt the entire process flow, causing shut down of the packaging process.
Additionally, with the advent of packaging machines capable of processing articles of different sizes, diameters, and article group configurations, attention has been focused on the development of modular article engaging mechanisms, including reinforcing flap folding devices. This allows for quicker changeover of the folding device needed to cooperate with the new article group configuration as prior to the development of modular article engagement devices, the article engagement devices were carried in a continuous chain or belt moving in timed relationship with the article group. Such an arrangement, however, is relatively inflexible, and is not desirable for use in contemporary multiconfigurable packaging machines.
An example of one such machine is disclosed in U.S. Pat. No. 4,563,853 to Calvert. This mechanism discloses a device which engages a carton to effect folding of a leading and a trailing flap. Considering that the entire process step requires a specific amount of time to complete, the mechanism is designed to track the carton movement for at least the time required to complete the operation. The device is mounted on an endless chain conveyor which is driven along the carton path of travel aligned and in timed synchronization with specific areas of the carton. One problem with this arrangement resides in the fact that such systems are not readily interchangeable or adjustable to accommodate various carton sizes or shapes which can be processed on a multiconfigurable packaging machine. Changeover to engage different types of cartons necessitated by the processing of various bottle sizes, styles and shapes may require either disassembly and reassembly of the entire conveyor, or the inclusion of a chain phasing mechanism.
Another, similar mechanism is disclosed in U.S. Pat. No. 4,970,843 to Lauret et al. This mechanism is also carried by a chain conveyor, and sequentially engages the carton's prescored flap area to then sequentially fold the carton flaps.
Examples of modular carton engaging mechanisms are shown in U.S. Pat. No. 4,612,753 to Taylor et al.; and in PCT Patent Application No. PCT/US94/10787. The Taylor patent discloses a tab locking mechanism, including locking fingers, which are carried by a rotating wheel. The above-referenced PCT application discloses a flap folding mechanism incorporated on the rotating wheel. While modular carton engaging or flap folding mechanisms may be more versatile than the prior chain conveying assemblies, all of the known flap folding devices, both modular devices and chain driven devices, including those referenced above, sequentially engage the adjacent prescored flap areas of the carton and sequentially fold the flaps inwardly. As discussed, this sequential folding can lead to the problem of carton shifting, which can result in interruption of process flow.
Therefore, while rotary, modular flap folding devices have been developed to provide for ease of adjustment or changeover, all known flap folding devices include the disadvantage of sequential flap folding which can lead to carton shifting.